Process for the production of percarboxylic acid

The conventional process for the production of a peracetic acid product, wherein hydrogen peroxide, acetic acid and water are fed into an aqueous reaction medium containing hydrogen peroxide, acetic acid, peracetic acid and an acid catalyst, wherein hydrogen peroxide and acetic acid react in the presence of the acid catalyst and form peracetic acid, and an aqueous peracetic acid concentrate is removed continuously from the reaction medium by distillation, has now been improved by feeding the acid catalyst continuously into the reaction medium and by withdrawing continuously a portion of the reaction medium as a bottom product. When the through flow of the reaction medium is thus increased, it is purified of impurities threatening the safety of the process. If the amount of acid catalyst in the reaction medium is further decreased, a product suitable, for example, for disinfection is obtained from the bottom product.